Recent advances in miniaturization, and particularly in the field of microelectro-mechanical structures (MEMS), have led to the development of microfluidic devices that are designed, in part, to perform a multitude of chemical and physical processes on a micro-scale. The attraction of these microsystems lies in the fact that miniaturization provides for substantial advantages in terms of cost, speed, the capability for easy automation, reproducibility, rapidity of analysis, and the need for only very small (μL) samples. As a consequence, microsystems in the form of microfluidic devices are becoming increasingly important in such diverse fields as DNA sequencing, immunochromatography, analysis and identification of explosives, chemical and biological warfare agents, and synthesis of chemicals and drugs.
Because only minute amounts of sample are required these microchemical analysis systems are particularly attractive for not only for rapid chemical analysis but also for the ability to analyze accurately a large number of samples in a short period of time. However, there remain problems in reproducibly detecting and measuring low concentrations of chemicals conveniently, safely and quickly.
Laser-induced fluorescence is one of the more sensitive detection methods available, being responsive to picomolar concentrations of analytes and thus, is ideally suited to the small volumes employed in capillary or microchip-based chemical analysis systems.